Commercial blasting explosive



Patented Jan. 8, 1935 UNITED STATES PATENT OFFICE Atlas Powder Company,W corporation of Delaware No Drawing. Application 11, Del., a

sci-m. No. aim-1': 3 01am. (01. 52-10) My invention is concerned solelywith commercial blasting explosives of the propulsive, rather thandetonating, type which contain sodi-' James E. Slusser, Serial No.532,341. The word intended above is used advisedly, because cartridgesmay contain smaller particles resultant from accidental breakage orerosion and yet be within the scope of my invention.

An important object of my invention is an in- I crease in strength ofexplosivesas described without material increase in burning speed. Infact, in usual application of the invention the theo-- retical situationindicates no increase or evena decrease in burning speed. Incidentalobjects are the accomplishment of the increased strength in aneconomical manner, without increased hazard, and by means of a materialthat is plentiful and continued supply. I The Slusser application abovereferred to discloses a molded black powder, wherein the body of powderis in such form and size as to bring about very advantageous results.

So-called pellet blasting powder is a comparatively new developmentinsofar as the United States is concerned and the Slusser molded powderis a very recent development insofar as the entire world is concerned.Bothtypes have in-, volved many new factors of manufacture, properties,application and economy as compared with the old, conventional grain'blasting powder.

uct as described in the patent application of Very important among thenew factors are those May 18,1933,

of black blasting powder, and of military explosives of a somewhatanalogous composition. For example, the prior art "has proposed theadmixture of finished grains of colloided nitrocellulose with finishedgrains of black blasting pow- 5 der. Such a procedure would be obviouslyusually unsatisfactory and uneconomical for my purpose for variousreasons, among which are that my powder may never exist in grain formand desirably should avoid the extra operations of dry- 10 ing andblending finished individual grains before proceeding to the operationsof forming my hardened masses of above prescribed sizes. Further theprior art suggests mixtures of uncolloided, merely nitrated cellulosewith military black'powder. To follow this procedure would be entirelyuneconomical for my purpose because merely nitrated cellulose is alwaysa primary and never a waste or salvage product and especially because itwould defeat my primary object of strength increase without speedincrease. Uncolloided nitrocellulose will increase the speed of blackpowder up to, under certain conditions of amount and type of admixture,even a detonating effect. Also, uncolloided nitrocellulose could not beintroduced economically to my powders without greatly increased hazard.Further, it has been proposed to. increase the strength of black powderby the introduction of ammonium nitrate. The proposed perchloratesincrease hygro-. scopicity, burning speed, hazard and cost.

Accordingly, my investigations and experiments convinced me that in noprior art were there satisfactory meansv for increasing the strength ofmy new types of commercial blasting 35 powder consistent with economy,safety, manufacturing convenience and accomplishment of desired powderquality and blasting efiects.

It is well known that there are, annually, relatively large quantitiesof smokeless powder- 40 colloided nitrocellulose-rejected as unfit forfurther military use. Some forms are colloided by means of non-explosivesolvents as ether-alcohol; others by means of explosive solvents asnitrogly'cerine. These rejected powders may, at times, be obtained atvery low cost. I

Specifically, my invention consists in the application of colloidednitrocellulose, as distinguished -from merely nitrated cellulose ornitrocellulose applied in liquid solution in a solvent, to commercialblasting powder of structure, composition and particle size previouslydescribed, in a manner to produce an important strength increaseeconomically, conveniently and without increased burning speed andhazard. It

also includes the product resulting from the foregoing practice. Mypreferred method of manufacture involves no addition to standardequipment at mills manufacturing the types of powder concerned.

That there may be no question regarding the.

theory of my invention I will explain as follows before discussing thedetailed application of the same. It is well known that colloidednitrocellulose functions in an entirely different manner from merelynitrated cellulose and obviously is the only form of nitrocellulose thatis practical for the practice of my invention which is the developmentof new forms of blasting powder of greatly increased strength withoutincrease in burning speed; in other words, the desirable form ofstrength increase resultant from increased gas volume, rather than theusually undesirable form of seaming, but not actual, strength increaseresultant from speed of burning increases which do not effect an actualincrease of total strength, but merely a more rapid gas evolution withthe consequently greater disintegrating action, which is undesirable formost applications of blasting powder. -It is obviously within the scopeof my invention to blend the colloided nitrocellulose by any preferredmechanical method to any preferred final product I with the normalblasting powder ingredients within the limits previously cited, sincethere is, in no case, a chemical reaction during fabrication, but a meremechanical mixture, whatever the original and final status of theindividual ingredient particles and whatever the mixing and dryingmethods.

In practice, I may proceed as follows: Assume wheel mill incorporatorsof a capacity of 500 lbs. of powder and a wish to use 10% of mystrengthening addition. I place 50 lbs. of wet colloided nitrocellulosein any form in the incorporator and run the wheels on it until it is ofthe desired particle size for the particular purpose then involved. Imay immediately add the composition containing sodium nitrate, carbonand sulphur of any preferred moisture content and continue the wheelingoperation. Water may be allowed to decrease by evaporation or increase,by addition, at will. The time of wheeling is incidental, dependent uponthe grade of final product immediately sought. The product from theincorporation may be packed into molds, re-

moved therefrom, dried and wrapped or in-- serted into the ultimatecartridge containers or it may be immediately packed in the ultimatecontainers and dried therein. These ultimate containers may be simplepaper wrappers or tubes as disclosed in the Slusser application. Where alow density, highly aerated product is desired, which indicates thatpacking intensity would be low and the molded product of insufficientmechanical stability to stand removal from molds and drying withoutbreaking up, I prefer the second procedure. In the former case,intensity of pressing inthe molds is the principal factor in a hard,permanently formed final product. In the latter case, crystallization ofthe water soluble content of the powder is the important factor inreaching an equivalent result, indicating that a higher moisture contentin the powder is preferable in the lattercase. I

It will be obvious that, in. either case, the incorporator product maybe subjected to any desired change in physicalcondition. such asgraining, prior to molding. It will also be obvious that mycolloidednitrocellulose may be partially wide range.

or wholly preprepared as to structure before going under the wheels ormay be mixed with the other ingredients prior to, during or afterwheeling. It is equally obvious that the nature of the incorporator maybe varied and other conditions may be varied to suit. The amount ofcolloided nitrocellulose used is dependent entirely upon the desiredstrength of the ultimate product. Generally, an addition of 10%colloided nitrocellulose will increase the strength of the ultimateproduct by about one-third as compared with the same product without thecolloided nitrocellulose.

In the field of the old, conventional grain blasting powder it waspossible to vary the blasting action by variation in grain size througha This was not resultant from an increase in total strength, but a merechange in time of gas evolution from the powder. The new forms of moldedblasting powder present no such capacity for adjustment to particularconditions. Consequently, it has not been possible to vary theblastingactions of these new forms to suit the coal, for instance, that is to bequence because the grades by testare very fre-.

quently found to overlap one another, or to approach one another soclosely that there is no practical difference. Expedients used ineiforts to vary the characteristics of pellet powders have been variedwheeling or incorporating times, varied physical conditions of theindividual ingredients prior to wheeling, various particle sizes andmoisture contents prior to molding, varied molding pressures and varieddegrees of aeration in every case ultimate results being uncertain to ahigh degree and the procedures costly and troublesome.

My invention permits of one systematic operating procedure, the onlyrequired variable being the amount of colloided nitrocellulose added andthe desired result is definitely predictable and assured, just as in thefield of high explosives the result may be assured by the nitroglycerincontent added.

' While theories, practices, preferred forms and limiting specificationshave been given by way of examples, explanations and clarifyingstatements, it will be apparent that variations within -the scope of thedisclosures and attached claims are part of my invention. From about twoper cent to about 20 percent colloided nitrocellulose is the practicalrange.

Colloided nitrocellulose in grain or particle form is an obviousmaterial to those skilled in the art, but definition by examples isgiven so that clarification may b complete. The product is instanced bysmokeless powder or picture film. As a matter of economy, salvaged scrapor "breakdown" material is usually used in my process.

Having described my invention, what I claim A commercial blasting unitin mass form composedof a mixture of black powder constitin the blackpowder constituents materially preclosing the particles of colloidednitrocellulose.

2. A commercial blasting unit in mass form of not lessvthan one inch inlength and .7 inch in di wants and colloided nitrocellulose materialwherewith each other in such manner as to form a uniform, homogeneousmixture in which the par-' ticles of the several ingredients are inclose and substantially uniform contact throughout the mass, with theblack \powder constituents embracing and enclosing the particles ofcolloided nitrocellulose.

3. The herein described process of preparing commercial blasting powderin mass form, which consists of molding together under at least somepressure a wetmass or black powder constituents and colloidednitrocellulose with the black powparticles. 7

ameter, composed of a mixture of black powder constituents in materiallypreponderating der constituents and colloided nitrocellulose quantitywhereby the latter constituents 'are wherein the black powderconstituents materially caused to embrace the colloided nitrocellulose15 preponderate in quantity and wherein the particles of the respectiveingredients are blended

